'NCIS: New Orleans' Zoe McLellan -- Scott Bakula Leaps to Co-Star's Defense in Custody War

Scott Bakula inserted himself in his "NCIS: New Orleans" co-star Zoe McLellan's bitter custody battle, telling the judge Zoe's focus is not her work or herself ... it's her son.

Zoe has joint custody of 2-year-old Sebastian. Zoe and the boy are living in New Orleans where the show is filmed, but ex-hubby Jean Pierre Gillain claimed it was unfair he had to travel from L.A. to visit his son. He claimed she was pawning the boy off to nannies while she worked.

But Bakula fiercely jumped to Zoe's defense, saying in a declaration, "Her life is and has been, about one thing and one thing only: being Sebastian's Mommy." The "Quantum Leap" star went on, "I have witnessed that every fiber of her being goes into providing a safe, nurturing, creative world for her son to grow up in."

Bakula explained Zoe has put her own life on hold ... to the point she once took the hair and makeup ladies to a concert, causing everyone to express how unusual it was that Zoe actually went out to have fun.

The actor ended by telling the judge, "Zoe has a huge heart and in my opinion, she is handling this tumultuous time of her life with great care, consideration and class."

In the end the judge didn't have to side with either parent, because Zoe and Jean Pierre settled their beef. It looks like the custody arrangement is pretty much status quo, but she has to pay him $4k a month in child support.